Method for the selective hydrogenation of vinyl oxirane to butylene oxide

ABSTRACT

1,2-Butylene oxide is prepared by catalytic hydrogenation of vinyloxirane over a heterogeneous catalyst produced by depositing one or more catalytically active elements of groups 7 to 11 of the Periodic Table of the Elements from the gas phase onto an inert, nonmetallic support.

This application is a 371 of PCT/EP96/03799, dated Aug. 29, 1996.

The present invention relates to an improved process for preparing1,2-butylene oxide by catalytic hydrogenation of vinyloxirane overheterogeneous catalysts.

The heterogeneous catalytic hydrogenation of vinyloxirane is known.

According to U.S. Pat. No. 2,561,984, the hydrogenation of vinyloxiranein ethanol over a palladium/activated carbon catalyst at 25° C./2 bargives n-butyraldehyde as main product after a reaction time of 3 hours.In contrast, Raney nickel as catalyst results in formation of mainlyn-butanol at 25° C. and 2 bar after a reaction time of 1.5 hours.Nothing is recorded about the formation of butylene oxide.

A paper by Aizikovich et al. (J. Gen. Chem. USSR, 28 (1958) 3076)describes the catalytic hydrogenation of vinyloxirane in methanol orethanol over platinum, palladium and Raney nickel catalysts. A supportedpalladium catalyst (1.8% by weight of palladium on calcium carbonate)results in formation of mainly n-butanol at 15° C./1 bar. In thisdocument, the most important intermediate in the hydrogenation isregarded as crotyl alcohol, although the formation of n-butyraldehyde isalso observed. In this paper too, there is no reference to formation of1,2-butylene oxide.

In U.S. Pat. No. 5,077,418 and U.S. Pat. No. 5,117,013 it is reportedthat the hydrogenation of vinyloxirane solutions overpalladium-containing catalysts gives n-butyraldehyde as main product.Thus, hydrogenation of vinyloxirane together with tetrahydrofuran assolvent over a palladium/activated carbon catalyst (5% by weight ofpalladium on activated carbon) at from 50 to 55° C. and a pressure of3.5 bar gives, after a reaction time of 3 hours, a hydrogenation productcontaining 55% of n-butyraldehyde, only 27% of 1,2-butylene oxide and 9%of n-butanol.

If the hydrogenation is carried out over supported catalysts containingpalladium on aluminum oxide (5% Pd/Al₂ O₃), only traces of 1,2-butyleneoxide are formed after a reaction time of 6 hours at from 25 to 55° C.and a pressure of 3.5 bar or after a reaction time of 4 hours at 100° C.and a pressure of 20.7 bar. Quantitative conversion givesn-butyraldehyde as main product at a selectivity of 87% or 78%.

In addition, the hydrogenation of vinyloxirane over Raney nickel ashydrogenation catalyst at 50° C. and 3.5 bar is described, with 58% ofn-butanol being formed as main product. The yield of 1,2-butylene oxideis, at 41%, low. In the hydrogenation of vinyloxirane over a supportedplatinum catalyst (1% by weight Pt/Al₂ O₃) at 100° C. and a hydrogenpressure of 20.7 bar, only 40% of 1,2-butylene oxide together with 23%of n-butanol, 24% of various butenols, 5% of crotonaldehyde and 3% ofn-butyraldehyde are found for complete conversion after a reaction timeof 4.6 hours. Other platinum-containing catalysts given even lower1,2-butylene oxide yields.

Furthermore, U.S. Pat. No. 5,077,418 and U.S. Pat. No. 5,117,013 teachthat high 1,2-butylene oxide yields are only obtained usingrhodium-containing catalysts. Varous supported rhodium catalysts (5% byweight of rhodium on activated carbon, 5% by weight of rhodium onaluminum oxide), which have a high content of the expensive noble metalrhodium, or hydrated rhodium oxide (Rh₂ O₃ ·xH₂ O) give 1,2-butyleneoxide contents of 60-93% in the hydrogenation of vinyloxirane solutions.A disadvantage of this process is the low space-time yield based on theamount of rhodium used. Thus, the space-time yield in Example 2 of U.S.Pat. No. 5,117,013 is only 119 kg of 1,2-butylene oxide/kg Rh*h.

Neftekhimiya 33 (1993) 131 describes the hydrogenation of vinyloxiraneover catalysts containing nickel, palladium and copper. Using Raneynickel or nickel on keiselguhr as catalyst, the hydrogenation proceedsprimarily with opening of the epoxide ring which leads to predominantformation of 1-butenols and n-butanol. The yields of butylene oxide arelow. For example, Raney nickel with methanol as solvent at 40° C./60 barhydrogen pressure gives, after a reaction time of 20 min at a conversionof 94%, a reaction product which, based on reacted vinyloxirane,contains 89% of butenols, 8% of n-butanol and only 2% of 1,2-butyleneoxide. The hydrogenation of vinyloxirane in methanol at 20° C./60 bar H₂using freshly prepared Raney nickel (20% by weight) also gives, after areaction time of 3 minutes at a conversion of 94%, only 9% of butyleneoxide in addition to 79% of n-butanol and 6% of butenol. A hydrogenationexperiment in methanol at 20° C./60 bar hydrogen pressure over a Raneynickel catalyst pretreated with isopropanol, nicotinic acid, pyridineand morpholine results, at 89% conversion, in the highest butylene oxideselectivity achievable using a nickel-containing catalyst, viz. 37%. Atthe same time, butenols and n-butanol are obtained in a selectivity of56% and 9% respectively.

With palladium-containing catalysts, higher butylene oxide selectivitiesare achieved in the hydrogenation of vinyloxirane compared with theexperiments using nickel-containing catalysts. For example, apalladium/activated carbon catalyst gives, without use of a solvent at15° C./60 bar hydrogen pressure after a reaction time of 13 minutes at61% conversion, 81% of butylene oxide based on vinyloxirane reacted. Onthe other hand, under the same reaction conditions but using methanol assolvent, a butylene oxide selectivity of only 53% is obtained at aconversion of 86%, with 13% of butanol and 18% of butenols being formed.A disadvantage of this process is that a high selectivity for theformation of 1,2-butylene oxide is achieved only at a relatively lowpartial conversion of the vinyloxirane. Since vinyloxirane and1,2-butylene oxide are very difficult to separate from one another bydistillation, this process is thus of no industrial importance.Palladium catalysts based on a polymer give, at a conversion of 68%,maximum butylene oxide selectivities of 60%, with butenols and n-butanolbeing formed in a selectivity of 18% and 4% respectively.

With copper-containing catalysts, a lower hydrogenation activity andresinification of the hydrogenation product is observed, making thisprocess industrially impractical. At reaction temperatures of 60-100 °C., 60 bar H₂ and 30% by weight of catalyst, a vinyloxirane conversionof 50% and a butylene oxide selectivity of 70% are achieved after areaction time of 3 hours.

German Patent Application P 44 22 046.4 relates to catalysts produced byimpregnation for use in the selective hydrogenation of vinyloxirane togive 1,2-butylene oxide. Despite the high selectivities describedtherein, relatively large amounts of butyraldehyde are formed asby-product.

German Patent Application P 44 07 486.7 teaches the hydrogenation ofvinyloxirane over catalysts which are obtained by vapor deposition ofthe catalytically active elements on a support of metal foil or wovenmetal mesh. These catalysts make possible a highly selective conversionto the desired process product, but the supports used are relativelyexpensive.

It is an object of the present invention to find an economical processfor preparing 1,2-butylene oxide from vinyloxirane in which 1,2-butyleneoxide is formed in high yield and selectivity. A further object is tofind catalysts for this purpose which, in comparison with the catalystsof the prior art, require significantly smaller amounts of expensivenoble metals as catalyst component. Finally, a process is to be found inwhich use is made of catalysts which can be produced from inexpensivesupport materials.

We have found that these objects are achieved by a process for preparing1,2-butylene oxide by catalytic hydrogenation of vinyloxirane over aheterogeneous catalyst wherein the catalyst used is produced bydeposition of one or more catalytically active elements of groups 7 to11 of the Periodic Table of the Elements from the gas phase onto aninert, nonmetallic support.

The process of the present invention surprisingly makes it possible toselectively hydrogenate the double bond of vinyloxirane in accordancewith equation (1), ##STR1## without the sensitive epoxide ring beinghydrogenolytically opened to any appreciable extent during thehydrogenation and without appreciable occurrence of other secondaryreactions, eg. isomerization of the vinyloxirane, for example tocrotonaldehyde which is subsequently hydrogenated to give crotyl alcoholand butanol.

The catalysts used according to the present invention can be produced bydepositing one or more elements of groups 7 to 11 of the Periodic Tableof the Elements, which have previously also been referred to astransition groups I., VII. and VIII., in particular copper, rhenium,ruthenium, cobalt, nickel, palladium or platinum or mixtures of theseelements onto a support, for example by physical vapor deposition (PVD)and/or chemical vapor deposition (CVD). Catalysts comprising palladium,cobalt, nickel, and also those comprising copper and nickel as activeelements are particularly preferred.

PVD and CVD processes are described, for example, in R. F. Bhunshah etal, "Deposition Technologies for Films and Coatings", NoyesPublications, 1982. Suitable PVD processes are, for example, evaporatingon, cathode atomization (sputtering) or electric arc coating, preferablycathode atomization. Known CVD processes are thermal CVD and plasma CVD.

In evaporating on, the coating material, ie. one or ore elements ofgroups 7 to 11 of the Periodic Table of the Elements, is introduced in amanner known per se into a suitable vapor source such as electricallyheated vaporizer boats or electron beam vaporizers. The coatingmaterial, in general a metal or an alloy, is then heated under reducedpressure, usually in the range from 10⁻⁷ to 10⁻³ mbar, causing a part ofthe coating material to be vaporized and deposit on the substrate as alayer, ie. according to the invention on inert, nonmetallic supports.The range at which the layer is evaporated on can be controlled by meansof the temperature of the vapor source.

In cathode atomization, the coating material is applied in solid form astarget to the cathode of a plasma system, atomized under reducedpressure (preferably from 5×10⁻⁴ to 1×10⁻¹ mbar) in a process gasatmosphere by application of a plasma and deposited on the support to becoated. The process gas usually contains a noble gas such as argon.

In electric arc coating, the coating material is removed from the sourceusing an electric arc which leads to a high degree of ionization of thecoating material in the process gas atmosphere. The support to be coatedcan be provided with a generally negative bias, which leads to anintensive ion bombardment during coating.

In CVD of the coatings of the present invention, a gas mixturecomprising at least one sufficiently volatile organometallic startingcompound of an element of groups 7 to 11 of the Periodic Table isintroduced into the coating chamber and decomposed by introduction ofthermal energy (thermal CVD) or under the action of a plasma (plasmaCvD), with the desired coating being formed on the support. The gasmixture used can additionally contain inert gases such as He, Ne, Ar, Kror Xe and further reactive gases. Deposition is carried out in apressure range of from 10⁻⁴ to 10⁺³ mbar. Suitable starting compoundsare, for example, carbonyl compounds, acetylacetonates andcyclopentadienyl compounds of the catalytically active elements.

For producing the coatings of the invention using the preferred methodof cathode atomization, various method variants such as magnetronsputtering, DC or RF sputtering, bias sputtering or reactive sputteringand also combinations thereof are suitable. In magnetron sputtering, thetarget to be atomized is located in an external magnetic field whichconcentrates the plasma into the region of the target and thus effectsan increase in the atomization range. In the case of DC or RFsputtering, the excitation of the atomization plasma is by means of a DCor an RF field. In bias sputtering, a generally negative bias is appliedto the substrate to be coated, leading to an intensive bombardment ofthe substrate by ions during coating.

The setting of the coating thickness, the chemical composition and themicrostructure of the coatings is carried out as described below by thecoating parameters process gas pressure, atomization power, sputteringmode, substrate temperature and coating time.

Selection of appropriate sputtering powers and coating times enables thethickness of the sputtered layer to be conveniently selected from a fewatomic layers to about 10 μm. For the process of the present invention,coating thicknesses of from 1 to 1000 nm are preferred.

Multicomponent active coatings can be produced by atomization of asuitable multicomponent target. Suitable targets are either homogeneousalloy targets which are produced in a known manner by melt processes orby powder metallurgical methods, or inhomogeneous mosaic targets whichare produced by joining smaller sub-pieces of different chemicalcomposition or by laying or gluing small disk-shaped pieces of materialonto homogeneous targets. Alternatively, metallic alloys can be producedby simultaneously atomizing two or more targets of different composition(simultaneous sputtering).

Using the deposition processes specified, it is also conceivable toproduce thin gradated coatings or multiple coatings whose composition isvaried in a defined manner with increasing coating thickness by means ofthe process parameters mentioned.

The microstructure (eg. phase distribution, crystallite shape and size,crystallographic orientation, porosity) of the active coatings canlikewise be controlled within wide limits by means of the processparameters specified. Thus, for example, magnetron atomization of ametal target in the pressure range from 4×10⁻³ to 8×10⁻³ mbar at coatingthicknesses of from 20 to 500 nm leads to relatively dense and pore-freecoatings, while above 10⁻² mbar a column-shaped morphology withincreasing porosity occurs. For coating thicknesses below about 50 nm,there is generally, depending on the roughness of the support, islandgrowth of the coatings. In addition to the sputtering pressure and thesupport, the substrate temperature and the ion bombardment duringcoating influence the microstructure of the coatings. For the process ofthe present invention, preference is given in the case of Pd activecoatings (20 nm) to, for example, a sputtering pressure of from 1 to10×10⁻² mbar.

To achieve uniform coating of the support, it is necessary for thesupport materials to be kept in motion during the coating procedureusing suitable mechanical or flow-mechanical apparatuses. Suitablemechanical apparatuses for this purpose are, for example, cages, drums,dishes or channels which are moved periodically and in which thesupports to be coated are brought into random motion. Alternatively, itis conceivable that the supports to be coated are kept in random motionby means of a fluidized-bed process (cf. DE-A 43 40 480).

Suitable supports for the catalysts able to be used in the process ofthe present invention are, for example, shaped bodies of glass, quartzglass, ceramic, titanium dioxide, zirconium dioxide, aluminum oxide,aluminosilicates, borates, steatite, magnesium silicate, silicondioxide, silicates, carbon, eg. graphite, or mixtures of the specifiedmaterials. Preference is given to steatite, silicon dioxide and aluminumoxide. The support can be porous or nonporous. Suitable shaped bodiesare extrudates, pellets, wagon wheels, stars, monoliths, spheres,chippings or rings. Particular preference is given to spheres, pelletsand extrudates. The selection of the shaped bodies is not restrictedprimarily by the method of production of the catalysts to be usedaccording to the present invention, but by the way in which the desiredcatalyst is used, for example as suspension or fixed-bed catalyst. Thus,spheres can have a size of, for example, from 100 μm to 2 mm, extrudatescan be from 1 to 5 mm thick and chippings can have a size of from 0.1 to10 mm.

By means of the techniques described for depositing the catalyticallyactive elements, it is possible to also apply promoters to the supportssimultaneously or successively. Suitable promoters are primarilyelements of group 4 of the Periodic Table of the Elements (formerly:transition group IV), in particular zirconium.

The catalysts thus produced can be used directly in the process of thepresent invention, but they are advantageously reduced prior to use inthe process of the present invention, generally using hydrogen orhydrogen-containing gases at, typically, from 50 to 300° C., preferablyfrom 80 to 250° C. The reduction is generally carried out until no morewater is formed. This reaction can eliminate oxide or adsorbate layersformed during deposition or by reaction of the catalytically activeelements with air. Hydrogen can be used diluted with inert gases such asCO₂, argon or nitrogen.

To carry out the process of the present invention, vinyloxirane orsolutions of vinyloxirane in a solvent which is inert under the reactionconditions is hydrogenated in the presence of the catalysts to be usedaccording to the present invention at generally from 0 to 200° C.,preferably from 10 to 130° C., in particular from 20 to 100° C. andparticularly preferably at from 25 to 60 ° C., at a pressure ofgenerally from 1 to 300 bar, preferably from 1 to 100 bar andparticularly preferably from 1 to 50 bar.

The process of the present invention can be carried out without solventor advantageously in the presence of a solvent which is inert under thereaction conditions. Such solvents can be, for example: ethers such astetrahydrofuran, dioxane, methyl tert-butyl ether, di-n-butyl ether,dimethoxyethane or diisopropyl ether, alcohols such as methanol,ethanol, propanol, isopropanol, n-butanol, isobutanol or tert-butanol,C₂ -C₄ -glycols, hydrocarbons such as petroleum ether, benzene, tolueneor xylene, N-alkyllactams such as N-methylpyrrolidone orN-octylpyrrolidone.

The process of the present invention can be performed eithercontinuously or batchwise. In the continuous procedure, it isadvantageous, for example, to use tube reactors in which the catalyst isarranged as a fixed bed over which the reaction mixture can be passed inupflow or downflow mode. In the batchwise procedure, either simplestirred reactors or, advantageously, loop reactors can be used.

The work-up of the reaction mixture for isolating the 1,2-butylene oxidecan be carried out in a conventional manner, eg. by distillation.

The vinyloxirane required as starting material can be prepared, forexample, by the process of U.S. Pat. No. 4,897,498 by partial oxidationof 1,3-butadiene over silver catalysts.

1,2-Butylene oxide is used, for example, as fuel additive or asstabilizer for chlorinated hydrocarbons.

EXAMPLES Example 1 Production of Catalysts by Cathode Atomization

a) Production of Catalysts of the Present Invention

The cathode atomization unit used was an Alcatel SCM 850 sputteringunit. Various supports in spherical form (eg. Table 1) were placed on around steel mesh (diameter 150 mm) having a mesh opening of about 1 mmand introduced into a cathode atomization unit. A target correspondingto Table 1 was used at a distance of 70 mm and the unit was evacuated.Argon was then introduced up to a pressure corresponding to Table 1. Byapplying a suitable potential to the target, a coating was deposited onthe support. During this procedure, the supports were moved randomly bymechanical agitation of the steel mesh so as to ensure homogeneouscoatings. The results are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                                                           Sputtering                                                                           Coating                             Cat. Support Sphere         Power  pressure                                                                             thickness                           No.  material                                                                              size    Target  W!     mbar!  nm!                                ______________________________________                                         1   Steatite                                                                              2 mm    Pd      250 (RF)                                                                            5 × 10.sup.-2                                                                   20                                  2   Steatite                                                                              2 mm    Pd      250 (RF)                                                                            1 × 10.sup.-2                                                                   20                                  3   Steatite                                                                              2 mm    Pd      250 (RF)                                                                            5 × 10.sup.-3                                                                    1                                  4   Steatite                                                                              2 mm    Pd      250 (RF)                                                                            5 × 10.sup.-3                                                                   10                                  5   Steatite                                                                              2 mm    Pd      500 (RF)                                                                            5 × 10.sup.-3                                                                   100                                 6   Steatite                                                                              2 mm    Pd      500 (RF)                                                                            5 × 10.sup.-3                                                                  1000                                 7   SiO.sub.2                                                                             1.5-    Pd      250 (RF)                                                                            5 × 10.sup.-3                                                                   20                                              3.5 mm                                                            8   Al.sub.2 O.sub.3                                                                      1.4-    Pd      250 (RF)                                                                            5 × 10.sup.-3                                                                   20                                              2.8 mm                                                            9   Glass   2 mm    Pd      500 (RF)                                                                            5 × 10.sup.-2                                                                  1000                                10   Steatite                                                                              2 mm    Ni.sub.30 Cu.sub.70 *                                                                 250 (DC)                                                                            5 × 10.sup.-2                                                                   10                                 11   Steatite                                                                              2 mm    Ni.sub.20 Cu.sub.80 *                                                                 250 (DC)                                                                            5 × 10.sup.-2                                                                   20                                 12   Steatite                                                                              2 mm    Ni.sub.30 Cu.sub.70 *                                                                 250 (DC)                                                                            5 × 10.sup.-2                                                                   100                                13   Steatite                                                                              2 mm    Ni     1000 (RF)                                                                            5 × 10.sup.-2                                                                    5                                 14   Steatite                                                                              2 mm    Co      250 (DC)                                                                            5 × 10.sup.-2                                                                   10                                 15   Steatite                                                                              2 mm    Cu      500 (DC)                                                                            5 × 10.sup.-2                                                                   10                                 16   Steatite                                                                              2 mm    Re      500 (DC)                                                                            5 × 10.sup.-2                                                                   10                                 17   Steatite                                                                              2 mm    Ru      500 (DC)                                                                            5 × 10.sup.-2                                                                   100                                ______________________________________                                         RF = RF potential;                                                            DC = DC potential;                                                            *mosaic target                                                           

b) Production of catalysts containing Pd/Zr and Pt/Zr

The catalysts shown in Table 2 were produced from amorphous alloys bycathode atomization, with one target (Pd₁,Zr₂) being used for thecatalyst No. 18 and 19 and two targets (Pt, Zr) being used for catalystNo. 20.

The catalysts No. 18 and 19 were subsequently further treated with ahydrogen/carbon dioxide mixture (14 l/h of H₂, 4 l/h of CO₂) at 280° C.for 24 hours.

The further treatment of catalyst No. 20 was carried out with asteam/nitrogen mixture (40 l/h of N₂, 3 g/l of H₂ O) at 320° C. for 24hours.

                                      TABLE 2                                     __________________________________________________________________________                                 Sputtering                                                                         Coating                                     Cat.                                                                             Support                                                                           Sphere  Power 1  Power 2                                                                            pressure                                                                           thickness                                   No.                                                                              material                                                                          size                                                                              Target 1                                                                           W!  Target 2                                                                           W!   mbar!                                                                              nm!                                        __________________________________________________________________________    18 Steatite                                                                          2 mm                                                                              Pd.sub.1 Zr.sub.2                                                                 500 (RF)                                                                           --  --   2.5 × 10.sup.-2                                                              1000                                        19 Glass                                                                             2 mm                                                                              Pd.sub.1 Zr.sub.2                                                                 500 (RF)                                                                           --  --     5 × 10.sup.-2                                                               300                                        20 Steatite                                                                          2 mm                                                                              Pt  350 (RF)                                                                           Zr  1000 (DC)                                                                            5 × 10.sup.-3                                                              1000                                        __________________________________________________________________________

Example 2

In an autoclave having a capacity of 50 ml, the solution to behydrogenated comprising 2.5 g of vinyloxirane and 22.5 g oftetrahydrofuran was admixed with 0.5 g of catalyst No. 1 without prioractivation with hydrogen and hydrogenated with hydrogen at 25° C. and 40bar for 8 hours while stirring. At a conversion of 100%, 91.7 mol% of1,2-butylene oxide, 1.0 mol% of n-butyraldehyde and 2.6 mol% ofn-butanol were obtained. Examples 3-22

2.5 g of vinyloxirane in 22.5 g of tetrahydrofuran were hydrogenatedwith H₂ at 40 bar over the catalysts 2-20 using a method similar to thatdescribed in Example 2. Table 3 shows the reaction conditions andcompositions of the hydrogenation products. The mol % figures are basedon vinyloxirane reacted. If the catalysts were activated before use,this was carried out at 250° C. in a hydrogen atmosphere.

                                      TABLE 3                                     __________________________________________________________________________                                Composition of                                    Catalyst          Reaction                                                                           VO   the reaction product                              Amount      Temperature                                                                         time conversion                                                                          mol %!                                           Ex.                                                                             No.                                                                               g! act.                                                                              ° C.!                                                                        h!   %!  BO n-Ba                                                                             n-BuOH                                      __________________________________________________________________________     3                                                                               2 1   +  25    8    100  88.0                                                                             1.4                                                                              3.3                                          4                                                                               3 1   -  50    8     73  66.0                                                                             1.9                                                                              11.4                                         5                                                                               4 1   -  50    4    100  82.4                                                                             1.6                                                                              4.0                                          6                                                                               5 1   -  50    6    100  79.4                                                                             2.3                                                                              8.3                                          7                                                                               6 1   -  50    4    100  81.3                                                                             2.2                                                                              3.8                                          8                                                                               7 1   +  20    6    100  82.2                                                                             3.2                                                                              4.7                                          9                                                                               8   0.5                                                                             -  50    2    100  79.2                                                                             2.6                                                                              4.2                                         10                                                                               9 1   +  50    2    100  82.1                                                                             2.1                                                                              3.0                                         11                                                                              10 1   +  50    6    100  87.8                                                                             2.7                                                                              8.1                                         12                                                                              10 1   +  25    8    100  88.5                                                                             1.5                                                                              5.3                                         13                                                                              11 1   +  50    6    100  86.0                                                                             2.5                                                                              8.5                                         14                                                                              12 1   +  50    8    100  82.4                                                                             2.0                                                                              6.2                                         15                                                                              13 2   +  20    8    100  86.0                                                                             1.8                                                                              6.0                                         16                                                                              14 2   +  20    6    100  83.2                                                                             2.3                                                                              8.0                                         17                                                                              15 1   +  50    8     68  89.1                                                                             1.1                                                                              2.2                                         18                                                                              16 2   +  50    8     66  86.4                                                                             1.5                                                                              4.3                                         19                                                                              17 1   +  50    8     41  91.0                                                                             0.1                                                                              2.1                                         20                                                                              18 1   +  50    4    100  81.2                                                                             2.5                                                                              4.7                                         21                                                                              19 1   +  50    6    100  83.1                                                                             2.0                                                                              3.7                                         22                                                                              20 2   +  50    8    100  80.4                                                                             2.7                                                                              6.9                                         __________________________________________________________________________     act. = activated                                                              VO = Vinyloxirane,                                                            BO = 1,2butylene oxide,                                                       nBA = nbutyraldehyde,                                                         nBuOH = nbutanol                                                         

We claim:
 1. A process for preparing 1,2-butylene oxide by catalytichydrogenation of vinyloxirane over a heterogeneous catalyst, wherein thecatalyst used is produced by deposition of one or more catalyticallyactive elements of groups 7 to 11 of the Periodic Table of the Elementsfrom the gas phase onto an inert, nonmetallic support.
 2. A process asclaimed in claim 1, wherein the catalytically active elements used arepalladium, cobalt, nickel or a mixture of copper and nickel.
 3. Aprocess as claimed in claim 1, wherein the inert support used issteatite, silicon dioxide or aluminum oxide.
 4. A process as claimed inclaim 1, wherein the ctalytically active elements are brought into thegas phase by cathode atomization.
 5. A process as claimed in claim 1,wherein catlaysts having a layer thickness of the catalytically activeelements of from 1 to 1000 nm are used.
 6. A process as claimed in claim1, wherein the catalysts are treated at from 50 to 300° C. with hydrogenprior to use.
 7. A process as claimed in claim 1, wherein not only thecatalytically active elements but also promoters from group 4 of thePeriodic Table of the Elements are deposited from the gas phase onto thesupport.